Communications systems are known and continue to evolve rapidly as is quite evident in wireless communications systems. Systems have and are being deployed that allow packet data enabled mobile stations access to packet data networks such as the Internet or internet like networks that utilize IP addresses and packet data transport protocols such as IP.
Business models are being developed and businesses built based essentially on the ubiquitous access they are provided to a market place and consumers given these systems. However these businesses generally must rely on users initiating access to their services and thus are induced to pay for advertising on popular web sites such as Yahoo's site or popular Internet service provider sites. More recently various business models have proposed using push approaches or applications whereby, rather than waiting for consumers, they endeavor to initiate contact with the consumer and push information to the users regarding their services and wares. There are known session initiation protocols such as IETF SIP that allow a host to initiate contact with a client provided the client has an IP address.
This is a problem with the popular version of IP addresses, known as IPv4 addresses because the address space is not large enough for everyone to have an IP address at all times. The industry has resorted to dynamic addresses to solve this problem whereby a given user shares a limited number of IP addresses with others and thus is assigned an IP address when and only so long as one is needed as determined by the user or the user's device. Future versions of the internet protocol are expected to use a much larger address space commonly referred to as IPv6 at which point everyone can have a so called static IP address. In the meantime and for legacy equipment, even after IPv6 has been adopted, hosts that wish to push content via an IP network to a user or consumer are faced with a problem of setting up an IP session with a user or specifically a device that does not have an IP address. This is particularly so in wireless systems that only recently have evolved to allow any form of Internet or packet based access.
Clearly a need exists for methods and apparatus for establishing an IP session between a host using SIP and a device without an IP address. Preferably this will be transparent to the host using a session initiation protocol such as IETF SIP.